GCE Biology For teaching from 2015 - WJEC(f) understand the meaning of catalysis; the lowering of...

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GCE Biology

For teaching from 2015

First AS Award: Summer 2016 First A Level Award: Summer 2017

The following pages feature an outline summary and content of new AS and A level specifications that are currently being developed for Wales. These details will be developed further before they are submitted to the regulators for accreditation.

Summary of assessment page 2 Subject content page 3

July 2014

DRAFT GCE Biology (Wales) 2

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GCE BIOLOGY (Wales)

SUMMARY OF ASSESSMENT

This specification is divided into a total of 5 units, 2 AS units and 3 A2 units. Weightings noted below are expressed in terms of the full A level qualification.

AS (2 units)

AS Unit 1 Basic Biochemistry and Cell Organisation Written examination: 1 hour 30 minutes 20% of qualification

A range of short and longer structured questions, some in a practical context and one essay.

AS Unit 2 Biodiversity and Physiology of Body Systems Written examination: 1 hour 30 minutes 20% of qualification


A Level (the above plus a further 3 units)

A2 Unit 3 Energy, Homeostasis and the Environment Written examination: 2 hours 25% of qualification


A2 Unit 4 Variation, Inheritance and Options Written examination 2 hours 25% of qualification

A range of short and longer structured questions, some in a practical context and one essay. Choice of one option out of four:

Immunology and Disease

Human Musculoskeletal Anatomy

Neurobiology and Behaviour

Food Science

A2 Unit 5 Practical Examination 10% of qualification


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SUBJECT CONTENT This section outlines the knowledge, understanding and skills to be developed by learners studying GCE Biology. Statements beginning with:

‘know’ require learners to recall information only

‘understand’ require deeper study and lend themselves to higher level explanation, analysis, interpretation and evaluation in addition to straightforward recall.

Learners should be prepared to apply the knowledge, understanding and skills specified in a range of theoretical, practical, industrial and environmental contexts. Practical work is an intrinsic part of this specification. It is vitally important in developing a conceptual understanding of many topics and it enhances the experience and enjoyment of biology. The practical skills developed are also fundamentally important to learners going on to further study in biology and related subjects, and are transferable to many careers. This section includes specified practical work that must be undertaken by learners in order that they are suitably prepared for the written examinations. The completion of this practical work will develop the practical skills listed in Appendix A. Appendix B lists the mathematical requirements with exemplification in the context of GCE Biology.


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UNIT 1 BASIC BIOCHEMISTRY AND CELL ORGANISATION

Written examination: 1 hour 30 minutes 20% of qualification

This unit includes the following topics:

1. Chemical elements are joined together to form biological compounds 2. Cell structure and organisation 3. Cell membranes and transport 4. Biological reactions are regulated by enzymes

5. Nucleic acids and their function 6. Genetic information is passed on to daughter cells


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Basic Biochemistry and Cell Organisation

1. Chemical elements are joined together to form biological compounds

Learners should: (a) know that key elements are present as inorganic ions in living organisms: Mg2+,

Fe2+, Ca2+, PO43–

(b) understand the importance of water in terms of its polarity, ability to form

hydrogen bonds, surface tension, as a solvent, thermal properties, as a metabolite

(c) know the structure, properties and functions of carbohydrates: monosaccharides

(triose, pentose, hexose sugars); disaccharides (sucrose, lactose, maltose); polysaccharides (starch, glycogen, cellulose, chitin)

(d) understand that alpha and beta structural isomerism in glucose results in storage and structural carbohydrates, illustrated by starch, cellulose and chitin

(e) understand the chemical properties which enable the use of starch and glycogen for storage and cellulose and chitin as structural compounds

(f) know the structure, properties and functions of lipids as illustrated by

triglycerides and phospholipids

(g) understand the implications of saturated and unsaturated fat on human health (h) understand the structure and role of amino acids and proteins

(i) understand the primary, secondary, tertiary and quaternary structure of proteins

(j) understand that proteins can be globular or fibrous and relate this to their

structure and function

Learners should be able to use given structural formulae (proteins, triglycerides and carbohydrates) to show how bonds are formed and broken by condensation and hydrolysis, including peptide, glycosidic and ester bonds. (Learners should be able to recognise and understand but not reproduce the structural formulae of the above molecules.)

PRACTICAL WORK

Food tests to include: iodine-potassium iodide test for starch; Benedict's test for reducing and non-reducing sugars; Biuret test for protein; emulsion test for fats and oils


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Basic Biochemistry and Cell Organisation 2. Cell structure and organisation

Learners should:

(a) understand the structure and function of the following: mitochondria;

endoplasmic reticulum (rough and smooth); ribosomes; Golgi body; lysosomes; centrioles; chloroplasts; vacuoles; nucleus; chromatin; nuclear envelope; nucleolus; plasmodesmata

(b) understand the structure of prokaryotic cells and viruses

(c) know how to compare the cell structures of eukaryotes(animal and plant),

prokaryotes and viruses (d) understand levels of organisation including aggregation of cells into tissues and

tissues into organs

PRACTICAL WORK

Calibration of the light microscope at low and high power, including calculation of actual size and magnification

Preparation and scientific drawing of a slide of living cells e.g. onion/ rhubarb/ Amoeba including calculation of actual size and magnification of drawing

Observation of a range of prepared slides showing examples of epithelia, muscle and connective tissue

Observation of a range of electron micrographs of prokaryote and eukaryote cells to show structure


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Basic Biochemistry and Cell Organisation

3. Cell membranes and transport

Learners should:

(a) know the principal units of the plasma membrane and understand the fluid-mosaic model

(b) understand factors affecting permeability of the plasma membrane (c) understand the following transport mechanisms: diffusion and factors affecting

the rate of diffusion; osmosis and water potential; pinocytosis; facilitated diffusion; phagocytosis; secretion (exocytosis); active transport and the influence of cyanide

PRACTICAL WORK

Determination of water potential by measuring changes in mass/length

Determination of solute potential by measuring the degree of incipient plasmolysis

Investigation into the permeability of cell membranes using beetroot


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Basic Biochemistry and Cell Organisation 4. Biological reactions are regulated by enzymes

Learners should:

(a) understand that metabolism is a series of enzyme controlled reactions

(b) understand the protein nature of enzymes

(c) know that enzymes may act intracellularly or extracellularly

(d) understand that active sites can be interpreted in terms of three dimensional structure

(e) understand the theory of induced fit as illustrated by lysozyme

(f) understand the meaning of catalysis; the lowering of the activation energy

(g) understand the influence of temperature, pH, substrate and enzyme concentration on rate of activity and inactivation and denaturation of enzymes and the importance of buffers for maintaining a constant pH

(h) understand the principles of competitive and non-competitive inhibition

(i) know the importance of immobilised enzymes and that industrial processes utilise immobilised enzymes enmeshed in an inert solid support, allowing enzyme reuse and improving stability

PRACTICAL WORK

Investigation into the effect of temperature or pH on enzyme activity

Investigation into the effect of enzyme or substrate concentration on enzyme activity


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Basic Biochemistry and Cell Organisation 5. Nucleic acids and their function

Learners should:

(a) know the structure of nucleotides (pentose sugar, phosphate, organic base) (b) understand the importance of chemical energy in biological processes

(c) understand the central role of ATP as an energy carrier and its use in the

liberation of energy for cellular activity

(d) know the structure of ATP

(e) understand the structure of nucleic acids: DNA bases: purines-adenine and guanine, pyrimidines-cytosine and thymine; complementary base pair rule; hydrogen bonding and the double helix; antiparallel strands

(f) be able to compare the structure of RNA and DNA

(g) know that the two major functions of DNA are replication and protein synthesis

(h) understand the semi-conservative replication of DNA which is catalysed by DNA polymerase and be able to use evidence from the Meselson and Stahl experiments for this

(i) understand the term genetic code

(j) understand the triplet code for amino acids

(k) know that exons are regions of DNA that code for proteins and that between the exons are regions of non-coding DNA called introns

(l) understand the transcription of DNA to produce messenger RNA

(m) understand that mRNA is translated using ribosomes and transfer RNA, which has an anticodon and a specific amino acid binding site, to synthesize proteins

(n) understand the 'one gene - one polypeptide' hypothesis

(o) know that polypeptides may be further modified and combined PRACTICAL WORK

Simple extraction of DNA from living material


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Basic Biochemistry and Cell Organisation 6. Genetic information is copied and passed on to daughter cells

Learners should:

(a) understand interphase (no subdivisions required) and the main stages of

mitosis

(b) understand the significance of mitosis as a process in which daughter cells are provided with identical copies of genes and the process of cytokinesis

(c) understand the significance of mitosis in terms of damage and disease: repeated cell renewal, damage repair and healing and unrestricted division leading to cancerous growth

(d) understand the main stages of meiosis (names of subdivisions of prophase 1 not required) and cytokinesis

(e) understand the differences between mitosis and meiosis

PRACTICAL WORK

Scientific drawing of cells from slides of root tip to show stages of mitosis

Scientific drawing of cells from prepared slides of developing anthers to show stages of meiosis


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UNIT 2 BIODIVERSITY AND PHYSIOLOGY OF BODY SYSTEMS Written examination: 1 hour 30 minutes 20 % of qualification This unit includes the following topics:

1. All organisms are linked through their evolutionary history 2. Adaptations for gas exchange 3. Adaptations for transport 4. Adaptations for nutrition


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Biodiversity and Physiology of Body Systems 1. All organisms are related through their evolutionary history

Learners should:

(a) know that organisms are classified into groups based on their evolutionary

relationships and that classification places organisms into discrete and hierarchical groups with other closely related species

(b) understand the need for classification and its tentative nature

(c) know the characteristic features of Kingdoms: Prokaryotae, Protoctista, Plantae, Fungi, Animalia

(d) understand the comparison with the three domain classification system

(e) understand that physical features and biochemical methods can be used to assess the relatedness of organisms, including that DNA ‘genetic fingerprinting’ and enzyme studies show relatedness without the problem of morphological convergence

(f) understand that all organisms are named according to the binomial system

(g) understand the concept of species

(h) know that biodiversity is the number and variety of organisms found within a

specified geographic region

(i) understand that biodiversity varies spatially and over time and can be affected by a wide range of factors

(j) know that biodiversity can be measured in a habitat by using random

sampling techniques e.g. Simpson’s Diversity Index, capture/ recapture, Lincoln Index

(k) understand that biodiversity has been generated through natural selection

PRACTICAL WORK

Investigation into biodiversity: fieldwork involving the use of quadrats, line transects or kick

sampling


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Biodiversity and Physiology of Body Systems 2. Adaptations for gas exchange

Learners should:

(a) understand the adaptations for gas exchange which allow an increase in body

size

(b) know that small animals exchange gases across their general body surface

(c) know how to compare gas exchange mechanisms in amoeba, flatworm and earthworm

(d) understand that larger animals have specialised respiratory surfaces with common features and that respiratory surfaces are adapted to environmental conditions- fish have gills for aquatic environments and mammals have lungs for terrestrial environments

(e) understand that large, active animals have ventilating mechanisms to maintain gradients across respiratory surfaces

(f) understand ventilation in bony fish and be able to compare counter current flow with parallel flow

(g) understand the structure and function of the human breathing system

(h) understand ventilation in humans and how gases are exchanged

(i) understand how the insect tracheal system is adapted to life on dry land

(j) know the structure of the angiosperm leaf

(k) understand the role of leaf structures in allowing the plant to function and photosynthesise effectively

(l) understand the role of the leaf as an organ of gaseous exchange, including stomatal opening and closing

PRACTICAL WORK

Dissection of fish head to show ventilation mechanisms

Scientific drawing of a low power plan of a prepared slide of T.S. leaf dicotyledon e.g. Ligustrum (privet), including calculation of actual size and magnification of drawing

Observation of T.S. lung

Observation of T.S. trachea


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Biodiversity and Physiology of Body Systems

3. Adaptations for transport Learners should:

(a) be able to compare the vascular systems of animal groups:

Insects

Earthworm

Mammal

Fish

open circulatory system, dorsal tube shaped heart, lack of respiratory gases in blood vascularisation, closed circulatory system and pumps, carriage of respiratory gases in blood double circulatory system single circulatory system

(b) understand the mammalian circulatory system including the structure and

function of heart and blood vessels and the names of the main blood vessels associated with the human heart

(c) understand the cardiac cycle and the maintenance of circulation to include graphical analysis of pressure changes, role of sinoatrial node and Purkyne/ Purkinje fibres and analysis of electrocardiogram traces to show electrical activity

(d) understand the function of red blood cells and plasma in relation to transport of respiratory gases, dissociation curves of haemoglobin of mammal (adult and fetus)

(e) understand how the dissociation curves of some animals are adapted to low oxygen level habitats e.g. llama, lugworm

(f) understand the Bohr effect and chloride shift

(g) know that nutrients, hormones, excretory products and heat are transported in the blood

(h) understand the formation of tissue fluid and its importance in exchange

(i) know the structure of the dicotyledon root

(j) understand the absorption of water by the root

(k) understand the movement of water through the root: apoplast, symplast and vacuolar pathways

(l) know the structure and understand the role of the endodermis

(m) know the detailed structure of xylem

(n) understand the movement of water from root to leaf including the transpiration stream and cohesion-tension theory

(o) understand the effect of environmental factors affecting transpiration


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(p) understand the adaptations shown by some angiosperms: hydrophytes, xerophytes

(q) know the detailed structure of phloem as seen by the light and electron microscope

(r) understand the translocation of organic materials from source to sink, including the ideas surrounding Phloem transport: diffusion; cytoplasmic strands; mass flow models; experimental evidence that solutes e.g. sucrose, are carried in the phloem; use of aphids and autoradiographs

PRACTICAL WORK

Investigation into stomatal numbers in leaves

Investigation into transpiration using a simple potometer

Scientific drawing of a low power plan of a prepared slide of T.S artery and vein, including calculation of actual size and magnification of drawing

Dissection of mammalian heart

Observation of erythrocytes and leucocytes in prepared blood smears

Observation of T.S. primary stem dicotyledon and root

Observation of T.S. leaf: marram grass and water lily


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Biodiversity and Physiology of Body Systems

4. Adaptations for nutrition Learners should:

(a) know that organisms can be autotrophic or heterotrophic

(b) know that autotrophic organisms can be photoautotrophic or

chemoautotrophic (c) understand that heterotrophic organisms can be:

saprotrophic/saprobiotic

holozoic

parasitic

(d) understand that saprotrophic nutrition involves the secretion of enzymes, external digestion of food substances followed by absorption of the products of digestion into the organism, e.g. fungi

(e) know that holozoic digestion is the internal digestion of food substances (f) know that in unicellular organisms, e.g. Amoeba, food particles are absorbed

and digestion is carried out intracellularly (g) understand that multicellular organisms show increasing levels of adaptation

from a simple, undifferentiated, sac-like gut with a single opening, e.g. Hydra, to a tube gut with different openings for ingestion and egestion and specialised regions for the digestion of different food substance

(h) understand that the human gut demonstrates adaptations to a mixed,

omnivorous diet that includes both plant and animal material (i) understand that different food substances require different enzymes and

different conditions for efficient digestion (j) understand that herbivore guts and dentition, in particular ruminants, are

adapted to a high cellulose diet while carnivore guts and dentition are adapted to a high protein diet

(k) understand that parasites are highly specialised organisms that obtain their

nutrition at the expense of a host organism e.g. Taenia and Pediculus PRACTICAL WORK

Observation of T.S. duodenum/ileum

Observation of skulls and dentition of a herbivore and a carnivore

Observation of specimens and slides of tapeworm e.g. Taenia


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UNIT 3

ENERGY, HOMEOSTASIS AND THE ENVIRONMENT Written examination: 2 hours 25 % of qualification 1. Importance of ATP 2. Photosynthesis uses light energy to synthesise organic molecules 3. Respiration releases chemical energy in biological processes 4. Microbiology 5. Population size and ecosystems 6. Human impact on the environment

7. Homeostasis and the kidney

8. The nervous system


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Energy, Homeostasis and the Environment

1. Importance of ATP

Learners should:

(a) understand that the synthesis of ATP involves a flow of protons through the enzyme ATP synthetase, the process of chemiosmosis and the electrochemical gradient

(b) understand the similarity between mitochondrial and chloroplast membrane function in providing a proton gradient for ATP synthesis

(c) understand that the proton gradient is maintained by proton pumps driven by

electron energy (d) know that the electron transport chain is formed from an alternate arrangement

of pumps and electron carriers (names of proton pumps and electron carriers in the electron transport system are not required)

PRACTICAL WORK

Investigation of dehydrogenase activity using artificial hydrogen acceptors, as illustrated by methylene blue or DCPIP or tetrazolium compounds


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2. Photosynthesis uses light energy to synthesise organic molecules

Learners should:

(a) understand the distribution of chloroplasts in relation to light trapping

(b) understand that chloroplasts act as transducers converting the energy of light photons into the chemical energy of ATP

(c) understand the process of light harvesting and the absorption of various wavelengths of light by chlorophyll and associated pigments and the energy transfer to reaction centres

(d) know the basic features of Photosystems I and II

(e) understand cyclic and non-cyclic photophosphorylation as sources of electrons for the electron transport chain

(f) understand photolysis as a source of electrons for Photosystem II

(g) understand that NADP is reduced by the addition of electrons and hydrogen ions in the stroma maintaining the proton gradient

(h) understand reduced NADP as a source of reducing power and ATP as a source of energy for the following reactions: the light independent stage and the formation of glucose; uptake of carbon dioxide by ribulose bisphosphate to form glycerate 3-phosphate catalysed by Rubisco

(i) understand that glycerate 3-phosphate is reduced to triose phosphate (carbohydrate) with the regeneration of ribulose bisphosphate

(j) know that other carbohydrates, lipids and amino acids can be made from the triose phosphate (no details of the chemistry of these processes is needed)

(k) understand the concept of limiting factors in relation to photosynthesis

(l) know the role of inorganic nutrients in plant metabolism as illustrated by the

utilisation of nitrogen and magnesium

PRACTICAL WORK

Investigation into the separation of chloroplast pigments by chromatography

Investigation into factors affecting the rate of photosynthesis

Investigation into the role of nitrogen and magnesium in plant growth


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3. Respiration releases chemical energy in biological processes

Learners should:

(a) know that all living organisms carry out respiration in order to provide energy in the cell

(b) understand that glycolysis is a source of triose phosphate, pyruvate, ATP and reduced NAD and results in the formation of acetyl CoA (the names of intermediates are not required)

(c) understand that the Krebs cycle is a means of liberating energy from carbon

bonds to provide ATP and reduced NAD with release of carbon dioxide (d) understand the role of reduced NAD as a source of electrons and protons for

the electron transport system

(e) understand the energy budget of the breakdown of glucose under aerobic and anaerobic conditions

(f) know how lipids and amino acids are utilised in respiration

PRACTICAL WORK

Investigation into factors affecting the rate of respiration in yeast


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4. Microbiology

Learners should:

(a) understand that bacteria may be classified according to their shape and by their reaction to the Gram stain as determined by their cell wall structure

(b) know the methods by which microorganisms can be cultured in the laboratory (c) understand the conditions necessary for bacterial growth and the principles of

aseptic technique

(d) understand methods used to monitor population growth in microorganisms including viable count, using serial dilutions, plating and counting colonies

PRACTICAL WORK

Investigation into the numbers of bacteria in fresh and stale milk, using techniques of serial dilution, plating and counting colonies

Preparation and observation of bacteria stained using Gram technique


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5. Population size and ecosystems

Learners should:

(a) understand populations and the way in which they grow - a simple quantitative treatment including immigration, emigration, birth and death rates

(b) understand graphs showing population growth and factors affecting

population growth; competition; carrying capacity

(c) understand the regulation of populations by density dependent and density independent factors

(d) understand the concept of ecosystems

(e) know that the sun is the source of energy for the ecosystem

(f) understand the concepts of habitat and community

(g) understand the transfer of biomass from plants to animals including trophic levels, efficiency of transfer; gross and net production and pyramids of biomass

(h) understand the principles of succession as illustrated by the change from bare rock to woodland

(i) know and be able to use the terms primary and secondary succession, pioneers, sere and climax community

(j) understand the importance of organic breakdown in recycling nutrients

(k) understand the carbon cycle

(l) understand the effects of human activities on the carbon cycle including that global warming and climate change affect distribution of species and are a possible cause of extinction

(m) understand the role of bacteria in the nitrogen cycle and the significance of nitrates in proteins and nucleic acids

(n) understand the importance of human activities such as ploughing and drainage in producing the aerobic conditions needed for nitrification and the economic importance of the nitrogen cycle in relation to food production and fertiliser application

(o) understand the process of eutrophication and algal blooms and that drainage has adverse effects on habitats


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6. Human impact on the environment

Learners should:

(a) understand reasons for species becoming endangered and causes of extinction (b) know how gene pools are conserved in the wild and in captivity (c) understand the issues in agricultural exploitation - conflicts between production

and conservation and possible means to resolve such conflicts as illustrated by deforestation and overfishing

(d) understand increased human pressures on the environment including the need

to achieve sustainability by changes in human attitudes and informed choices (e) understand the need for political decision making to be informed by knowledge

based on sound scientific principles (f) understand the concept of planetary boundaries


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Energy, Homeostasis and the Environment 7. Control systems co-ordinate and regulate processes

Learners should:

(a) understand the concept of homeostasis and its importance in maintaining the

body in a state of dynamic equilibrium

(b) understand the role of negative feedback in restoring conditions to their original levels

(c) understand the structure of the mammalian kidney including nephron (d) know the functions of the mammalian kidney including nitrogenous excretion

and water regulation (e) understand the adaptations of the cells of the proximal tubule for reabsorption (f) know that endocrine glands contribute to homeostatic balance as illustrated

by the role of the posterior pituitary gland in the secretion of antidiuretic hormone

(g) understand the role of antidiuretic hormone (h) understand the need for different excretory products and adaptations of the

loop of Henlé in different environments PRACTICAL WORK

Dissection of kidney

Observation of prepared sections of kidney

Observation of electron micrographs of sections of kidney


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8. The nervous system Learners should:

(a) know that responding to a stimulus requires information from a receptor to be

relayed to an effector

(b) know that effectors are either muscles or glands (c) know the main areas of the spinal cord (d) understand the basic pattern of spinal nerves in relation to the spinal cord

including the dorsal root and ventral root (e) understand the simple reflex arc as the basis for protective, involuntary

actions (f) understand the structure of a nerve net and be able to draw comparisons with

the nervous systems in more complex organisms (g) know the structure of a motor neurone including drawing and labelling of

diagram (h) understand the nature and transmission of the nerve impulse (i) know how to analyse oscilloscope traces

(j) understand factors affecting speed of conduction in other organisms (k) know the structure and understand the role of a synapse (l) understand the process of synaptic transmission (m) understand the effect of chemicals e.g. organophosphates and psychoactive

drugs on transmission of impulses

PRACTICAL WORK

Observation of T.S. spinal cord


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UNIT 4 VARIATION, INHERITANCE AND OPTIONS Written examination: 2 hours 25 % of qualification This unit includes the following topics:

1. Sexual reproduction in humans 2. Sexual reproduction in plants 3. Inheritance 4. Variation and evolution 5. Application of reproduction and genetics Choice of one option from four: A. Immunology and Disease

B. Human Musculoskeletal Anatomy

C. Neurobiology and Behaviour D. Food Science


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Variation, Inheritance and Options

1. Sexual reproduction in humans

Learners should:

(a) understand the structure and function of the reproductive systems in humans

(b) understand the processes of spermatogenesis and oogenesis to produce

spermatozoa and secondary oocyte; sexual intercourse; fertilisation and implantation

(c) understand endocrine control of reproduction in the female: including the menstrual cycle, birth and lactation by reference to follicle stimulating hormone, luteinising hormone, oestrogen, progesterone, oxytocin and prolactin and human chorionic gonadotrophin production by the embryo

(d) understand the role of the placenta including hormonal control

PRACTICAL WORK

Observation of histology of ovary and testis


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2. Sexual reproduction in plants Learners should:

(a) know the generalised structure of flowers to be able to compare wind and

insect pollinated

(b) understand the development of pollen and ovules (c) understand cross and self-pollination and the process of double fertilisation

(d) understand the formation and structure of seed and fruit as shown by broad

bean and maize

(e) understand the process of germination of Vicia faba (broad bean)

(f) understand the effect of gibberellin

PRACTICAL WORK

Investigation of the digestion of starch agar using germinating seeds

Dissection of wind and insect-pollinated flowers

Scientific drawing of a low power plan of a prepared slide of anther, including calculation of actual size and magnification of drawing

Observation of prepared slides to show histology of ovary


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3. Inheritance Learners should: (a) know alleles are different forms of the same gene

(b) understand the principles of monohybrid and dihybrid Mendelian inheritance

(c) understand the use of a Chi squared test

(d) understand simple crosses involving codominance and linkage

(e) understand sex linkage as illustrated by haemophilia and Duchenne muscular

dystrophy

(f) understand gene mutation as illustrated by sickle cell anaemia and chromosome mutation as illustrated by Down's syndrome

(g) know the effect of mutagens, carcinogens and oncogenes (h) understand that gene expression can be controlled by factors other than

changes in the DNA sequence, the study of this is called epigenetics PRACTICAL WORK

Experiment to illustrate gene segregation including the use of the Chi squared test in testing the significance of genetic outcomes


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4. Variation and evolution Learners should:

(d) know that genetic and environmental factors produce variation between

individuals

(b) understand that variation may be continuous and discontinuous; heritable and non-heritable

(c) understand that there is inter and intra-specific competition for breeding success and survival

(d) understand that there are selective agencies (e.g. supply of food, breeding sites, climate, human impact)

(e) understand the concept of gene pool and genetic drift

(f) understand that selection can change the frequency of alleles in a population

(g) understand and be able to use the Hardy-Weinberg principle and equation

(h) understand the conditions under which the Hardy-Weinberg principle applies

(i) understand the concepts of isolation and speciation

(j) understand that populations can be separated by geographical, behavioural, morphological, seasonal and other isolation mechanisms including hybrid sterility

(k) understand Darwin's theory of evolution that existing species have arisen through modification of ancestral species by natural selection

PRACTICAL WORK

Investigation of continuous variation in a species (including use of the Student’s t-test)


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5. Application of reproduction and genetics Learners should:

(a) know that the Human Genome Project was completed in 2003 and was used

to locate and sequence alleles of human chromosomes and this has been extended to study variation in the human genome amongst 100 000 people in the UK (100K Genome Project)

(b) understand the ethical issues surrounding the use of this knowledge and its

application to the screening of embryos for genetic disorders e.g. cystic fibrosis, Huntington's disease, Thalassemia

(c) know that the genomes from other organisms have also been sequenced including the mosquito, Anopheles gambiae and the Plasmodium parasite that it transmits, better methods to control malaria may be developed as a result

(d) understand the use of PCR to amplify short sections of repeating non-coding DNA or microsatellites which are visualised using electrophoresis to produce a genetic fingerprint, and its use in solving crime and proving paternity

(e) understand the formation of recombinant DNA by insertion of foreign DNA into bacterial plasmids and the cloning of the bacteria to produce useful molecules as illustrated by insulin

(f) understand issues surrounding the use of gene technologies to produce genetically modified crops by inserting a gene from one organism into another to convey disease resistance or a desired characteristic e.g. GM tomatoes and soya

(g) understand the advantages and disadvantages of using gene therapy for the treatment of disease as illustrated by muscular dystrophy

(h) understand the use of genomics and its possible impact on healthcare of the future

(i) understand the issues surrounding the use of stem cells for replacing damaged tissues and organs


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OPTIONS (choice of 1 option from 4)

OPTION A: IMMUNOLOGY AND DISEASE


1. Disease Learners should:

(a) understand the meaning of the following terms: pathogenic, infectious, carrier,

disease reservoir, endemic, epidemic, pandemic, vaccine, antibiotic, antigen, antibody, resistance, vector, toxin, antigenic (sero) types

(b) know that the human body acts as a host to other living organisms

(c) understand the following diseases in terms of: the types of organisms; source of infection; tissue affected; mode of transmission; prevention; control methods and treatment, including vaccines: Bacterial infections: Cholera; Tuberculosis

Viral infections: Smallpox; Influenza

Protoctistan infections: Malaria

(d) understand the relationship between the pathogenicity of viruses and their

mode of reproduction

2. Antibiotics

Learners should: (a) know that bacterial infections can be controlled by antibiotics which can be

bacteriostatic or bactericidal in their mode of action and that antibiotics can be broad or narrow spectrum

(b) understand the modes of action of penicillin and tetracycline and how the structure of the bacterial cell wall in Gram negative bacteria affords protection against many antibiotics and immune defences

(c) understand how the overuse of antibiotics has resulted in the spread of

antibiotic resistance amongst pathogenic bacteria


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3. Immune response Learners should:

(a) know that the natural barriers in the body help to reduce the risk of infection,

these include natural skin flora, connective tissue, localised inflammation, phagocytosis, clotting, tears, mucus and ciliated epithelium

(b) understand how specific immune responses are developed as a result of exposure to foreign antigens

(c) understand that humoral immune responses involve the production and

secretion of antigen-specific antibodies (d) know that cell mediated immunity involves the destruction of pathogens,

infected cells and cancerous cells by direct cell contact (e) understand the role of T lymphocytes and B lymphocytes in cell-mediated and

humoral immune responses (f) understand that a specific immune response can be induced naturally or

artificially to produce an active, long-lived response or can be acquired passively resulting in short-term protection

(g) understand that the principles of the active immune response can be used

medically to immunise against disease, e.g. Rubella, without infection by the disease

(h) know that injection of antibodies can provide passive, emergency treatment to

protect against an infection, e.g. the treatment of rabies (i) understand that immunisation programmes against different diseases have

different levels of effectiveness

(j) know that ethics must be taken into consideration when designing vaccination programmes


© WJEC CBAC Ltd.

OPTION B: Human Musculoskeletal Anatomy Human Musculoskeletal Anatomy

1. Skeletal tissues

Learners should: (a) know the structure of cartilage including Hyaline cartilage, yellow elastic

cartilage, white fibrous cartilage

(b) understand the cause and treatment of osteoarthritis

(c) understand the cause and treatment of rheumatoid arthritis. (d) know that compact bone consists of a matrix containing 30% organic (mainly

the protein collagen) and 70% inorganic (the main unit being hydroxy-apatite containing calcium and phosphate)

(e) know the functions of the organic and inorganic units of compact bone (f) understand that bone is constantly being broken down and reformed by cells

called osteoblasts embedded in the matrix which lay down the inorganic unit of the matrix and osteoclasts which break it down

(g) understand the structure and function of the Haversian systems (h) know that rickets is a disorder of bone caused by a calcium or vitamin D

deficiency (i) understand the causes, symptoms and treatment of osteoporosis and brittle

bone disease (j) know the structure and ultra-structure of skeletal muscle (k) understand sliding filament theory to include structure of the thin filaments

(actin with two accessory proteins, tropomyosin and troponin) and thick filaments ( myosin)

(l) know how to compare ‘fast twitch’ and ‘slow twitch’ muscles (m) understand the effects of anaerobic conditions including the role of creatinine

phosphate and the build up of lactic acid in muscles (n) understand the use of glycogen and protein as the main sources of energy

during muscle contraction


© WJEC CBAC Ltd.

Human Musculoskeletal Anatomy

2. Structure and function of human skeleton

Learners should: (a) understand the structure of the appendicular skeleton (pectoral and pelvic

girdles, forelimb and hind limb)

(b) know the names of the bones forming the appendicular skeleton and the axial skeleton

(c) know the structure and function of the vertebral column and general structure of a vertebra

(d) understand the differences between cervical, thoracic and lumbar vertebrae

and be able to relate them to their function (e) understand the functions of the skeleton, including support, muscle

attachment, protection, production of red blood cells and as a store of calcium

3. Joints

Learners should: (a) know the different types of joint in the human; immovable/fused; gliding joints;

hinge; ball and socket

(b) understand the concept of joints acting as levers including examples of 1st order, 2nd order and 3rd order levers

(c) understand the structure of a typical synovial joint including the roles of cartilage, synovial fluid, ligaments

(d) understand antagonistic muscle action in the human forelimb including the

role of tendons


© WJEC CBAC Ltd.

OPTION C: Neurobiology and Behaviour Neurobiology and Behaviour

1. The Brain

Learners should: (a) know the structure of the human brain – the position of the cerebrum,

hypothalamus, hippocampus, cerebellum, and medulla oblongata

(b) understand the main functions of the cerebrum, hypothalamus, cerebellum and medulla oblongata

(c) understand the role of the sympathetic and parasympathetic nervous systems

(d) understand that the hypothalamus is the link between the nervous and endocrine regulation

(e) understand the role of the sensory areas and motor areas of the cortex

(f) understand that there is a relationship between the sizes of the relevant parts of the cerebrum and the complexity of innervation of the different parts of the body as illustrated by the sensory homunculus and the motor homunculus

(g) understand the role of the areas of the cerebrum involved in language

comprehension and speech

2. Neuroscience

Learners should: (a) understand that there are different techniques used for studying the brain

without invasive neurosurgery including Magnetic Resonance Imaging (MRI), Computerised Tomography (CT), Positron Emission Tomography (PET) and Electroencephalography (EEG)

(b) understand how the brain develops and that there are critical periods for certain aspects of human learning and language acquisition

(c) know that neuroplasticity refers to changes in neural pathways (d) know that changes in neural pathways enable the brain to respond to

changes in the environment and to compensate for injury or disease

(e) understand how the expression of genes can affect brain development and the impact this may have on an individual’s behaviour

(f) understand how altered gene expression in childhood could predispose adults

to an increased risk of mental illness


© WJEC CBAC Ltd.

Neurobiology and Behaviour

3. Behaviour

Learners should: (a) understand innate behaviour and the advantage to organisms of escape

reflexes, kineses and taxes as exemplified by woodlice (b) understand that many animals / vertebrates demonstrate learned behaviours;

be able to describe habituation, imprinting, classical and operant conditioning

(c) understand that primates, including humans, live in very complex societies and exhibit behaviours such as imitation and insight

(d) understand the advantages and disadvantages of living in social groups

(e) understand that social structure in insects is based on a caste system and

that communication between individuals is brought about by innate behaviours

(f) understand that social structure in vertebrates is achieved through dominance

hierarchies where animals are able to recognise each other as individuals and possess some abilities to learn

(g) understand the advantage of territorial and courtship behaviours in increasing

reproductive success

(h) understand the role of sexual selection in the evolution of territorial and courtship behaviours


© WJEC CBAC Ltd.

OPTION D: FOOD SCIENCE

Food Science

1. Food and health Learners should:

(a) understand the terms metabolism, anabolism, catabolism, metabolic rate and

basal metabolic rate

(b) understand the variation of basal metabolic rate with age, sex and activity

(c) understand the concept and units of a balanced diet

(d) know functions and sources of carbohydrates (sugars, starches, NSP (non-

starch polysaccharides)), proteins, fats, oils, vitamins A, B, C and D, calcium,

iron, iodine, and water

(e) understand the health consequences of ingesting excess fat, including obesity, atherosclerosis, arteriosclerosis, coronary heart disease, type II diabetes

(f) understand the health consequences of ingesting excess sugar including

obesity, coronary heart disease, type II diabetes and oral health

(g) know that excess salt in the diet has been correlated with increased blood

pressure in some individuals

(h) understand how to calculate body mass index (i) understand the limitations of body mass index (j) understand undernutrition and the consequences of ingesting too little protein,

iron, vitamins A, C and D, iron and calcium (k) understand diets in relation to weight loss, to medical conditions including

diabetes and PKU and to medications including statins

(l) understand the potential for harm in food ‘fads’ (m) understand some causes of food poisoning in terms of: the types of

organisms; source of infection; symptoms; control methods and treatment


© WJEC CBAC Ltd.

Food Science

2. Food and botany Learners should:

(a) know the range of plant families used as food, e.g. cereals are Poaceae;

peas, beans, pulses are Fabaceae; potatoes and tomatoes are Solanaceae, apples and pears are Malvaceae

(b) know the range of plant parts used as food, e.g. seeds, fruits, stems, leaves,

roots, tubers, flowers and buds

(c) understand the biochemical and hormonal control of ripening and fruit

formation, including the formation of seedless fruit

(d) know examples of the use of selective breeding in crop plants

(e) understand how polyploidy has contributed to the production of crop plants

3. Food preparation and distribution

Learners should:

(a) know some natural and artificial food additives and their functions including

flavouring, flavour enhancers, colouring, preservatives and nutritional

(b) understand the legal framework for the use of food additives, including the use of E numbers

(c) understand the role of Food Standards Agency in regulating food standards (d) understand the issues related to the use of E numbers, including links to

hyperactivity disorders

(e) understand that the problem of food distribution and food loss between farm and plate has been addressed in part by applying technology to food packaging, food preservation and food distribution

(f) understand the concept of food miles and the effect on the carbon footprint


© WJEC CBAC Ltd.

UNIT 5 PRACTICAL EXAMINATION

10% of qualification

This unit is currently under development.


© WJEC CBAC Ltd.

APPENDIX A WORKING SCIENTIFICALLY This appendix is currently under development.


© WJEC CBAC Ltd.

APPENDIX B MATHEMATICAL REQUIREMENTS AND EXEMPLIFICATION The following table illustrates where mathematical skills may be developed and could be assessed. Those shown in bold type would be tested in the A2 units.

Mathematical skills

Exemplification of mathematical skill in the context of A level Biology (assessment is not limited to the

examples given below)

Arithmetic and numerical computation

Recognise and make use of appropriate units in calculations

Learners may be tested on their ability to:

convert between units, e.g. mm3 to cm3 as part of volumetric calculations

work out the unit for a rate e.g. breathing rate

Recognise and use expressions in decimal and standard form


use an appropriate number of decimal places in calculations, e.g. for a mean

carry out calculations using numbers in standard and ordinary form, e.g. use of magnification

understand standard form when applied to areas such as size of organelles

convert between numbers in standard and ordinary form

understand that significant figures need retaining when making conversions between standard and ordinary form, e.g. 0.0050 mol dm-3 is equivalent to 5.0 x 10-3 mol dm-3

Use ratios, fractions and percentages


calculate percentage yields

calculate surface area to volume ratio

use scales for measuring

represent phenotypic (monohybrid and dihybrid crosses)

Estimate results Learners may be tested on their ability to:

estimate results to sense check that the calculated values are appropriate

Use calculators to find and use power, exponential and logarithmic functions


estimate the number of bacteria grown over a certain length of time


© WJEC CBAC Ltd.

Handling data

Use an appropriate number of significant figures


report calculations to an appropriate number of significant figures given raw data quoted to varying numbers of significant figures

understand that calculated results can only be reported to the limits of the least accurate measurement

Find arithmetic means Learners may be tested on their ability to:

find the mean of a range of data, e.g. the mean number of stomata in the leaves of a plant

Construct and interpret frequency tables and diagrams, bar charts and histograms


represent a range of data in a table with clear headings, units and consistent decimal places

interpret data from a variety of tables, e.g. data relating to organ function

plot a range of data in an appropriate format, e.g. enzyme activity over time represented on a graph

interpret data for a variety of graphs, e.g. explain electrocardiogram traces

Understand simple probability Learners may be tested on their ability to:

use the terms probability and chance appropriately

understand the probability associated with genetic inheritance

Understand the principles of sampling as applied to scientific data


analyse random data collected by an appropriate means, e.g. use Simpson’s Diversity Index to calculate the biodiversity of a habitat

Understand the terms mean, median and mode


calculate or compare the mean, median and mode of a set of data, e.g. height/mass/size of a group of organisms

Use a scatter diagram to identify a correlation between two variables


interpret a scattergram, e.g. the effect of life style factors on health

Make order of magnitude calculations


use and manipulate the magnification formula magnification = size of image size of real object

Select and use a statistical test Learners may be tested on their ability to select and use:

the chi squared test to test the significance of the difference between observed and expected results

the Student’s t-test

the correlation coefficient


© WJEC CBAC Ltd.

Understand measures of dispersion, including standard deviation and range


calculate the standard deviation

understand why standard deviation might be a more useful measure of dispersion for a given set of data e.g. where there is an outlying result

Identify uncertainties in measurements and use simple techniques to determine uncertainty when data are combined


calculate percentage error where there are uncertainties in measurement

Algebra

Understand and use the symbols: =, <, <<, >>, >, ∝, ~.

No exemplification required.

Change the subject of an equation


use and manipulate equations, e.g. magnification

Substitute numerical values into algebraic equations using appropriate units for physical quantities


use a given equation e.g. Simpson’s Diversity Index

Solve algebraic equations Learners may be tested on their ability to:

solve equations in a biological context, e.g. cardiac output = stroke volume x heart rate

Use logarithms in relation to quantities that range over several orders of magnitude


use a logarithmic scale in the context of microbiology, e.g. growth rate of a microorganism such as yeast

Graphs

Translate information between graphical, numerical and algebraic forms


understand that data may be presented in a number of formats and be able to use these data, e.g. dissociation curves

Plot two variables from experimental or other data


select an appropriate format for presenting data, bar charts, histograms, graphs and scattergrams

Understand that y = mx + c represents a linear relationship


predict/sketch the shape of a graph with a linear relationship, e.g. the effect of substrate concentration on the rate of an enzyme-controlled reaction with excess enzyme

Determine the intercept of a graph


read off an intercept point from a graph, e.g. compensation point in plants


© WJEC CBAC Ltd.

Calculate rate of change from a graph showing a linear relationship


calculate a rate from a graph, e.g. rate of transpiration

Draw and use the slope of a tangent to a curve as a measure of rate of change


use this method to measure the gradient of a point on a curve, e.g. amount of product formed plotted against time when the concentration of enzyme is fixed

Geometry and trigonometry

Calculate the circumferences, surface areas and volumes of regular shapes


calculate the circumference and area of a circle

calculate the surface area and volume of rectangular prisms, of cylindrical prisms and of spheres e.g. calculate the surface area or volume of a cell

GCE Biology Outline/ED 14/7/14

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